Question

我是POJO的新手，正致力于创建从Google API中表示JSON的对象。如何为这个JSON创建一个pojo？

"notificationSettings": {
    "notifications": [
     {
      "type": "eventCreation",
      "method": "email"
     },
     {
      "type": "eventChange",
      "method": "email"
     },
     {
      "type": "eventCancellation",
      "method": "email"
     },
     {
      "type": "eventResponse",
      "method": "email"
     }
    ]
   }

我已经找到了JSON的其余部分，但是，Gson.fromJSON（）一直返回null。

编辑1

这就是我所拥有的

private static class NotificationSettings{

        public NotificationSettings(){

        }

        public NotificationSettings(Map<String, List<Notification>> notifications) {
            super();
            this.setNotifications(notifications);
        }

        public Map<String, List<Notification>> getNotifications() {
            return notifications;
        }

        public void setNotifications(Map<String, List<Notification>> notifications) {
            this.notifications = notifications;
        }

        private Map<String, List<Notification>> notifications;


    }

    private static class Notification{

        public Notification(){

        }

        public Notification(String type, String method) {
            super();
            this.type = type;
            this.method = method;
        }

        private String type;
        private String method;
        /**
         * @return the type
         */
        public String getType() {
            return type;
        }
        /**
         * @param type the type to set
         */
        public void setType(String type) {
            this.type = type;
        }
        /**
         * @return the method
         */
        public String getMethod() {
            return method;
        }
        /**
         * @param method the method to set
         */
        public void setMethod(String method) {
            this.method = method;
        }


    }

编辑2 另一个问题是需要参数的构造函数吗？另外，是否还需要toString（）方法？

谢谢！

Answer 1

POJO是一个普通的旧Java对象，它是一个包含字段和getter / setter的类。我不认为使用Java的人对POJO来说是新手，除非它正在学习Java。这就是为什么我不会给出确切的班级结构，否则我会做你的工作。

您只需要为JSON字符串中的元素定义类型。让我们回顾一下这个字符串，你如何映射它：

"notificationSettings": { //name of class: NotificationSettings
    "notifications": [ //array of Notification objects. It means you will need a Notification class as well
                       //and an array or List field called notification in NotificationSettings class
     { //this defines the structure for Notification class
      "type": "eventCreation", //String field called type
      "method": "email" //String field called method
     },
     {
      "type": "eventChange",
      "method": "email"
     },
     {
      "type": "eventCancellation",
      "method": "email"
     },
     {
      "type": "eventResponse",
      "method": "email"
     }
    ]
}

从您的实施中，您应该将private Map<String, List<Notification>> notifications;字段替换为private List<Notification> notifications;，并使Notification类成为其自己文件中的顶级类。

这个复杂的JSON的POJO

1 个答案: